About 45 candidates are alleging that the winners of seven seats on Riyadh's 14-member council circulated an endorsement from a group of Muslim scholars in the hours before the polls opened. The complaining candidates said the last-minute "blessings" were delivered to voters through mobile-phone text messages and the Internet, and violated campaign rules banning candidates from running as a coordinated slate.

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"There is no proof yet, but the complaints appear to be moving forward," said an adviser to the commission that planned and staged the elections. "Given the number of candidates in the race, I fully expect more to join the complaint."

The Thursday elections were for half of the seats on 38 municipal councils in the greater Riyadh region and drew more than 1,800 candidates. The elections, the kingdom's first in more than four decades, amounts to an experiment by the ruling Saud family in opening the political system to more public participation. The government appoints the remaining seats.

The councils have little political power and are responsible only for urban planning policy and oversight of city finances. But the elections are being viewed as an indication of how Saudis might vote if elections are called for more influential offices, such as the appointed national consultative council. Municipal elections are scheduled to be held in eastern Saudi Arabia next month, followed by voting in the west in April.

Some of the candidates who have complained characterized the seven winners of the Riyadh races as Islamists, although impartial observers said only five of those in the race used religion as the basis of their campaigns. The description is a difficult one to assess, given that the kingdom's constitution is already based on the Koran and most every resident is a practicing Muslim, although some favor more separation of religion from government affairs.

Saudi officials said candidates had five days to file complaints to an independent election commission, which is to make a final decision on their merits. Only about a quarter of the 550,000 eligible voters in the capital region registered to cast ballots. The elections excluded women and members of the military.

Saudi officials said 65 percent of registered voters cast ballots in Riyadh, a city of nearly 5 million people, and 82 percent turned out in the surrounding towns, where candidates from large tribes and families appeared to have won the majority of seats.